System of electric power distribution



G. L. CLAYBOURN 1 2,325,663

Filed Feb'. 13, 1942 2 Sheets-Sheet l SYSTEM OF ELECTRIC POWER DISTRIBUTION SSS Aug. 3, 1943.

G. L. cLAYBoURN 2,325,663

SYSTEM OF ELECTRIC POWER DISTRIBUTION Aug. 3, 1943.

Filed Feb. 15, 1942 2 'sheets-sheet 2 WITNESSS; l

F ,4 5 C' 676/7 C/OU/W. 4

Patented Aug. 3, 1943 SYS-TEM 0F ELECTRICv POWER DISTRIBUTION Glen L. Claybourn, Pittsburgh, Pa., assignerto Westinghouse Electric & Manufacturing Company, VEast Pittsburgh, Pa., a. corporation of Pennsylvania Application E Tebruaryl, 194,2, Serial No. 430,704

(Cl. ISI- 97) Y8 Claims.

My, invention relates, generally, to systems of electric power'distribution `andjmore particuf larly, to three-phase, four-wire distribution systems having main and transfer buses and feeder circuits energized from said buses.

In systems of the foregoing type, it is customary to provide voltageregulators for the feedf er circuits. In order to permit a feeder regulator to be Vtaken out; of service Without interrupting the supply of'power to the feeder circuit, the feeder is temporarily connected to thetransfer bus. In prior systems, the transfer has been made by manually operable disconnecting switches, which is not entirely satisfactory, par-y ticularly from the standpoint of safety.k

An object of my invention, generally stated, isv

to provide a system of distribution which, shall be simple and efficient in operationand which may be readily installed.

A more specific object of my invention is to provide a system of distribution inv which all switching operations are performed by automatic circuit breakers,

Another object of my invention is Yto utilize a minimum number of circuit breaker units for performing the required switching operations in a system of distribution.

A further object of my inventionis to reduce the space required for the switchgear apparatus in a power distribution system. Y

Other objects of my invention will be explained fully hereinafter or will be apparent` to thosev skilled in the art.

In accordance with my invention, the main feeder bus of a system of distribution is connect-y ed to an auxiliary device, `such as the induction voltage regulator of a single-phase feeder circuit, through one pole of a two-pole circuit breaker unit. The regulator or auxiliary device is connected to the single-phase feeder circuit through the second pole of the same two-pole breaker unit. A single-pole breaker unit is utilized to connect the feeder circuit to the transfer bus. In this manner, the main bus and the regulator orauxiliary device are protected and isolated by objects of my invention, reference .mayV be hadV to the following detailed description,'takei1 in. conjunction with the accompanying drawings, in which:

Figure l is a diagrammatic view of a system of, distribution embodying my invention; and

Fig. 2V is a diagrammaticview of a modification of the invention.y

Referring to Fig. 1. of the drawings, the system showny therein comprises a pair, of three-phase main buses I and 2, a three-phase transfer bus 3, a neutral busv 4, and a.4 plurality of single-phase feeder circuits F. Power is supplied to the main busk I through a three-phase line I0, which is connectedto the vmain bus I by means of a threepole, circuit breaker II. Likewise, power is supplied to the main bus 2 through a three-phase line 20, connected to the bus 2 by means of a three-pole circuit breaker 2l.

Theinain buses I and 2 may be connected together by a pair of ythree-pole circuit breakers I2. Thetransfer bus 3`may be energized from either the main bus I"or the main bus A2, or from both buses in case both of the bus tie breakers I2 are c1osed',`by closing a three-pole circuit breaker 22.

As explained hereinbefore, it is the usual practice in power distributionrsystems to provide an induction voltage regulator for each one of the feeder circuits to maintain a desired voltage on the `feeder circuit. In the present system, an induction voltage regulator I3 Ais provided for each one of the feeder circuits F which are energized from the main bus I, andan induction voltage regulator 23 is provided for each feeder circuit energized from the main busy 2. Asshown, the current.coils of theV regulatorsare connected in series circuit relation with the feeder circuits, and the potential coils are connected between the feeder conductors and the neutral bus 4, thereby being responsive to the potential impressed cn each feeder circuit.

vIt .is alsoV the usual practice to provide for transferring each feeder circuit from the main bustothe transfer bus in the event that it is de-` sired to takek the voltage regulator or other auxiliary device out of service, thereby maintaining power on the feeder circuit while the regulator is out of service. In prior systems, manually operated disconnect switches have been provided for performing a part of the switching operatic-ns necessary to take a regulator out of service.

' Innorder to simplify the switching operations required for taking a regulator out of service, and also to increase the safety to the operator performing the switching operations, a two-pole cirf cuit breaker I4 and a single-pole circuit breaker I5 are provided for each one of the feeder circuits energized from the main bus I, and, similarly, a two-pole circuit breaker 24 and a single-pole feeder circuit through the second pole ofthe same two-pole breaker unit.V The feeder circuit may also be connected to the corresponding phasejm of the transfer bus 3 by the single-pole circuit two main buses I and 2 are connected together'V by a three-pole bus tie breaker l2.

A two-pole circuit breakerunit and a singlepole circuit breaker unit are provided for each one of the feeder circuits, therebyaffording cornplete protection and isolation of each voltage regulator, as described hereinbefore; jAs shown, one poleof the two-pole breaker unit connects the --regulator to the main feeder bus, and the other breaker unit. In this manner, the main bus andfV the regulator are protected and isolated by thel operation of a single breaker unit. At the same time, the single-pole breaker unit may beclosed v to maintain electrical energy on the feeder circuit from the corresponding phase of the transferV or auxiliary bus. Y

It is apparent from the foregoing descripticn and the diagram that the present system provides for easyv and safe maintenance orvreplacement of a breaker unit and itsjassociatedfregulator or other auxiliary device. j Also, only two switch`y ing operations are required to take a regulator out, of service-first, the closingof a single-pole breaker, and then V'the openin'g'of a two-pole breaker, therebyY completely isolating the regula; tor. y Furthermore, the transfer of power is accom, plished by Vdevices designed for interrupting power circuits. The present method increases the safety of operation as compared vwith the conventional method'oftutilizing a single-pole breaker with isolating disconnecting switches and transfer disconnecting switches. The ,transferringV of power by means of disconnecting switches in a large feeder station adds to the possibility of confusion and the danger of transferring a circuit thatisl not properly set up and coordinated for transfer,

v thereby endangering both life and-equipment; While not necessarily limited thereto, the present three-phase, four-wire .distribution system with circuit breaker controlled'single-phase feeder circuits provides'a'fiexible arrangement "which is particularly suitable for application in substations Vutilizing metal-clad switchgear in,y which the busesand circuit. breakers are enclosed in metalA housings, thereby furtherincreasing'the safety'of the equipment;

The system shown in Fig. 2 of theV drawings is particularly suitable forapplication in. stations utilizing metal-clad switc'hgear ofthe type disclosed vand claimed in my cfopending application,` Serial' No. V430,703, led February 13, i942, and assigned tothe Vassignee of this invention.v The two main buses l and 2 supply groups of 'singl'ef phase feeder breaker structures'disposed at right angles to the main bus, and each main buis 'sup-" pliesone-half of each single-phase feeder"s'truc. ture.' `The single-phase feeder structuresV are each provided with'a main bus', which is in two Y sections, such as ia and 2a,'and a tranlsferlbus such as 3d, which extends the full length of each singl'e-phaseY structure. 4A neutral bus, suchas lia, also extends the-'full length of each singlephase structure.

Each section of a single-'phase feederV busis connectedto the proper phase of a main bus by a single-pole circuitbreaker unit; thus the main feederbus Yto, isc'onneoted to phase'Aof the main bus' 'l byfa single-pole breaker Het.' Likewise, the

Vmainfeed'er bus Za 'is connectedY to phasefA of Vthe main bus 2 by a single-pole breaker 2id.

Likewise, the main feeder buses for phases B and Care ccnnected'to the proper phases of the main buses by similar single-pole breaker'units. Thev pole connects the regulator to the feeder circuit. TheY feeder circuit may be connected to the transfer bus for the corresponding phase by the single-- pole circuit .breaker unit.

VInrthepresent system, the transfer bus for each. 4phase is connected tothe main feeder bus forl the corresponding phase through an induction regulator 33 by means of a two-pole breaker I.

In this manner, provision is made for maintainingaregulated voltage on each transfer bus, thereby' providing aV regulated voltage on each feeder circuit when they areV supplied froinuthe transfer:V

bus;

The foregoing arrangement provides the ulti-f mateY flexibility in switchingcontrol, Vthe maxi-- mum continuity of electrical energy Ventlie'feedeiM circuits,V andalso provides, all the advantages. of safety, yease of maintenance and 'continuity 'of" service, which are characteristicsjof metal-clad. switchgear. However, Vas explained hereinbe fore, the systems'herein disclosed'are not limited' to metal-clad'switchgeaig but may-be applied to; systems utilizing'switchgear of other types. If desired, the operation of the circuit breakers'. for isolating the induction regulators and con necting the feeder circuits tothe transfer bus; may vbecontrolled automatically by relays Vre sponsive toA predetermined conditions. Th s, ini oase of a fault in one ofthe regulators the i lays will automatically effect the transfer' of thefeeder circuit tothe transfer bus and the iscv lationpf Vthe regulator withoutrequiring the at tentionof a station attendant-thereby maintain-1 ing continuity of power on the feeder. f

Since znany modifications maybe-made in the; apparatus and arrangement of parts without departing from the spirit of my inventiong do not'v wish to be limited other than'bythe scope of the: appended claims. Y

l. Ina system of distribution, in combination; a main bus', a transfer bus, a feeder circuit, a regulator for the feeder icireuit, a multi-pole cirbreaker unit for connecting the'feeder cir-` cuit to the main' busin series-circuit Y,relation withvthe regulatorgsaid breaker unit being Vdisposed to iselatethe regulator from the main bus,i the transfer bus andthe feeder circuit, and aY single-pole circuitV breaker unit for,V connecting the feeder circuit to thetransfer bus.; l 2. In a'system of distribution, in combination,

a main' bus, a transfer bus, Va', feeder; circuit,l aV

regulator `for the feeder circuit, a multi-pole circuit jbreakerY unit for connecting the feeder'` k3. In'a system of distribution'in combination,,

a main bus, a' transfer bus, a feeder circuit, aV

regulator 'for' the feeder circuit, a tWo-polecircuit breaker unit for connecting the feederpir"A K Y cuit to the main bus in series-circuit relation with the regulator, said breaker unit being disposed to isolate the regulator from the main bus, the transfer bus and the feeder circuit, and a single pole circuit breaker unit for connecting the feeder circuit to the transfer bus, the two poles of the two-pole breaker unit being operable simultaneously and the single-pole breaker unit being operable independently of the two-pole breaker unit.

4. In a system of distribution, in combination, a main bus, a feeder circuit, an auxiliary device for the feeder circuit, and a multi-pole circuit breaker unit for connectingr the feeder circuit to the main bus through said auxiliary device, said auxiliary device being connected to the main bus through one pole of the breaker unit and to the feeder circuit through another pole of the breaker unit, thereby isolating said device from the main bus and the feeder circuit when the breaker is open.

5. In a system of distribution, in combination, a main bus, a feeder circuit, a regulator for the feeder circuit, and a multi-pole circuit breaker unit for connecting the feeder circuit to the main bus in series-circuit relation with the regulator, said regulator being connected to the main bus through one pole of the breaker' unit and to the feeder circuit through another pole of the breaker unit, thereby isolating said regulator from the main bus and the feeder circuit When the breaker is open.

6. In a system of distribution, in combination, a main bus, a transfer bus, a feeder circuit, a regulator for the feeder circuit, a two-pole circuit breaker unit for connecting the feeder circuit to the main bus in series-circuit relation with the regulator, and a single-pole circuit breaker unit for connecting the feeder circuit to the transfer bus, said regulator being con- -a main bus, a

nected to the main bus through one pole of the two-pole breaker unit and to the feeder circuit through the other pole of the two-pole breaker unit, thereby isolating said regulator' from the main bus and the feeder circuit when the twopole breaker is open.

7. In a system of distribution, in combination, a main bus, a transfer bus, feeder circuit, a regulator for the feeder circuit, a two-pole circuit breaker unit for connecting tne feeder circuit to the main bus in series-circuit relation with the regulator, and a single-pole circuit breaker unit for connecting the feeder circuit to the transfer bus, said regulator being connected to the main bus through one pole of the two-pole breaker unit and to the feeder circuit through the other pole of the two-pole breaker unit, thereby isolating regulator from the main bus and the feeder circuit when the two-pole breaker is open, said single-pole breaker unit being operable independently of the two-pole breaker unit. Y

S. In a system of distribution, in combination,

transfer bus, a feeder circuit, a regulator for the feeder circuit, a two-pole circuit breaker int for connecting the feeder circuit to the main bus in series-circuit relation with the regulator, and a re-poie circuit breaker unit for connecting the feeder circuit to the transfer bus, said regulator being connected to the main bus through one poie of the two-pole breaker unit and to the feeder circuit through the other pole of the two-pole breaker unit, thereby isolating said reguiator from the main bus and the feeder circuit when the twopole breaker is open, the two poles of the two-pole breaker unit being operable simultaneously and the single-pole breaker unit being operable independently of the two-pole breaker unit.

GLEN L. CLAYBOURN. 

